Construction of an extremely simple CPU

I'm looking to build an extremely simple CPU, just to learn more about how they're built.

Im not looking to make it run any modern programs (with my limited resources im not going to be able to cram enough transistors into it to achieve more than a couple of Hz...

Anyway, how would I start about building a simple CPU?

Thanks
--James

learn about circuits, gates, etc. I took a small electronics course and we used IC chips to build simple counting devices, then changed it so it gave me back a reading in binary. It is what you said, REALLY simple.

Yep. I created a device that would count how many people walked past it, and would show the figures on 2 seven segement displays. It worked perfectly appart from one of the displays i put in upside down . Took me ages to get the correct pins for etc too!

I'll get some pics up in a bit. For a bit of a giggle.

actually...i have a program that i lifted (legally) off of my computer. It's called circuit maker. Every circuit I made with the electronics I tried to make with this program...and it works quite well. not for the big circuits (90 million transistor CPU), but for a simple counter or even a complex counter it'll work nicely.

Their's one called crocodile clips in the UK. Well that's what we used back in skool for electronics.

Yeah you plan out your circuit with the program, get all your components in place, and then see if you can reduce the size of the pcb, etc, and get it all neat.

Ah memories of croc clips...

Although it was powered by Macromedia Flash so I automatically despise it...

its like programming, just with actual stuff. Really great stuff, I might do more of it during MEEG.

You may also look into the "Digital Works" Suite. This suite provides you with many tools to program and build/simulate designs before implementation. It works great.

Well here is my circuit. It was a while ago i did it, just dusted it off.

The casing i did for it was a bit of a mess, so i thought i'd leave that out




My soldering is alot neater nowadays lol!

nice, i used a breadboard in my electronics class. I pissed off the teacher because he would give me a new project, and in an hour tops (that was the most complicated one where you pressed a button and it raised a counter on a seven segment display) I had finished it. got the electrical schematic for that monster there?

You mean the plans? i could dig them out. But they are all done on large sheets of planning paper.

Doubt you could read them from my digital camera, it's shit.

But if you really want them yeah i'll get them.

nah was just wondering. interesting stuff. If you have even a basic understanding of how gates, resistors, capacitors, diodes, etc. work you can build some great stuff.

Very true. I've forgotten half of what i was taught. But i got a B in the subject when i did it. Shame they didn't have an electronics course for A level, i'd have done it straight away.

I'm gonna buy a basic book on it, and reteach myself, and make some daft stuff. I love fiddling!

you can use it to make nice additions to case mods. switches, lighting, etc.

Oh yeah, i know the real basics. I've got a key/lock wired up to my power switch, so i can stop people from turning it on. Unless they know what their doing and they just use a screw driver on the jumpers. But don't let them know that.